TN84%5 i 48-2E
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PRODUCT SPE
/IFICATION AND USER'S MANUAL
NOTICE
This document, and the information contained herein, is copyright by Tandon Corporation and
may not be duplicated or reproduced, in whole or in part, without the prior written approval of
Tandon Corporation.
This document is intended to provide the user with detailed information adequate for the efficient
installation, operation, and service of the equipment involved.
However, while every effort has been made to keep the information contained herein current and
accurate as of the date of publication, no guarantee is given or implied as to its accuracy.
TM848-1E, TM848-2E
THINLINE™ FLEXIBLE DISK DRIVE
48 TRACKS PER INCH
PRODUCT SPECIFICATION AND USER'S MANUAL
lcllld D I1 CORPORATION
CHATSWORTH, CALIFORNIA 91311
20320 PRAIRIE STREET
o COPYRIGHT 1983 TANDON CORPORATION
CONTENTS
Section
Number
SECTION 1 G E N E R A L DE SCRIPTION
Page
Number
Title
1.1
1.2
1.3
1.4
Introduction
Scope Of The Document.. .. . . . . . . . . . . . . . . . . . . .
Purpose Of The Drive
Major Features
Microprocessor Control
Write Protect .
Daisy Chain Capability
Internal Trim Erase
Industry Standard Interface Compatibility .
Activity Indicator .
Direct Drive, Brushless D. C. Motor
Compact Size
Diskette Lever Lock Solenoid
Functional Description
Power On Self- Tests
Physical Description
1-1
1-1
1-1
1-1
1-1
1-1
1-1
1-2
1-2
1-2
1-2
1-2
1-2
1-2
1-3
1-3
1.5
SECTION 2 PRODUCT SPECIFICATIONS
Introduction .
Mechanical Specifications .
Electrical and Operational Specifications
Reliability Specifications
Environmental Specifications .
2-1
2-1
2-1
2-1
2-1
3.4
3.1
3.2
3.3
2.1
2.2
2.3
2.4
SECTION 3 OPERATION
Introduction
Unpacking The Drive
Preinstallation Checkout
Mounting The Drive .
Dust Cover .
Cooling .
Interface Connections
Input Control Lines
Output Control Lines ..
Typical Interface Characteristics
D. C. Power .
Drive Address and Option Strapping
Drive Select (DS1 — DS4)
Head Select Options (Sl — S3 and 1B — 4B) .
Stepper Motor Power (PS, PS*, DS, HL) .
Spindle Motor Control Options (Ml, M3, M4, MOL, MOH, MC1 — MC4)
Ready and True Ready (R and TR)
Lever Lock Options (D, DL, LL, NL)
Disk Change (DC) .
Two-Sided Diskette Installed (2S),
Write Protect (WP and NP) .
Write Current Switch (XC and IC)
Diagnostic Mode of Operation (DM, DL, Ml, M3, M4) .
3-1
3-1
3-1
3-1
3-2
3-2
3-2
3-2
3-5
3-6
3-6
3-8
3-8
3-8
3-10
3-10
3-13
3-13
3-13
3-13
3-13
3-14
3-14
3.5
3.6
Section
Number
Page
NumberTitle
3-14
3-14
3-14
3-17
Diskettes
Loading The Diskette
Write Protect Yab .
Diskette Handling and Storage
ILLUSTRATIONS
FIGURES
Figure
Number
Page
Number
n r
1-1
2-1
2-2
4-o
Title
Disk Drive
Disk Drive Outline Drawing
+24 Volt D. C. Current, Configuration 1
+ 24 Volt D. C. Current, Configuration 2
Electrical Interface Characteristics .
Control and Data Timing Requirements
LSI Circuit Board Assembly .
Non-LSI Circuit Board Assembly .
Recording Media
Diskette Care and Handling .
1-4
2-2
2-5
2-5
3-6
3-7
3-11
3-12
3-17
3-18
3-1
3-2
3-3
3-4
3-5
3-6
TABLES
Table
Number
Page
Number
2-1
2-2
2-3
3-1
3-2
3-3
3-4
Title
Electrical and Operational Specifications .
Reliability Specifications .
Environmental Specifications
Drive Interface Lines and Pin Assignments
D. C. Power Connector Pin Assignments ..
Option Patching
Diagnostic Mode Of Operation
2-3
2-6
2-6
3-3
3-8
3-9
3-15
11
SECTION 1
GENERAL DESCRIPTION
INTROOU CTION
intelligent t erm i n a l control lers, mic r o-
computers, word processing systems, data com-
munication systems, error logging, program
loading, and point-of-sale terminals.
This document provides required information
in order to evaluate or incorporate Tandon's
disk drive into a system.
Tandon Corporation's Model Nu m b ers
TM848-1E and TM848-2E, eight-inch flexible
drives are full-feature, microprocessor-
controlled drives. They may be installed in
one-half the space normally required for an
eight-inch drive. They are compact data stor-
age devices that use an IBM-formatted, indus-
try standard, eight-inch diskette. Both drives
are 48 tracks per inch recording devices.
The Model TM848 series of drives are capable
of reading an d writ in g in si ngle-density
format on a diskette, using a proprietary
read/write head patented by Tan don. I n
addition, both drives have a double density
capability when Modified Frequency Modula-
tion (MFM) or other appropriate recording
techniques are used. The encoding and decod-
ing of the data is done by the user's controller.
The Model TM848-1E drive uses one side of
the diskette for data s t orage. The Model
TM848-2E drive doubles data storage capabili-
ties by using both sides of the diskette.
1.1 SCOPE OF THE DOCUMENT
1.3 MA JOR FEATURES
MICROPROCESSOR CONTROL
The TM848-1E and TM848-2E drives feature
an onboard microprocessor. This microproces-
sor provides six major features:
1. Buffered seek capabilities..
2. Improved head positioning accuracy
with reduced hysteresis.
3. Write c urrent switching for o ptimal
data recording quality.
4. True Ready signal.
5. Internal diagnostics (strappable).
6. Power On Self- Tests.
WRITE PROTECT
When a write protected diskette is inserted
into the dr i ve, t h e wr i t e el e ctronics are
disabled.
This document contains a description of the
major features, physical and functional speci-
fications, mounting and power requirements,
the interface, and typical timing characteris-
tics of the TM848-1E and TM848-2E drives. DAISY CHAIN CAPABILITY
1.2 PURPOSE OF THE DRIVE
The drive provides the address selection and
gating functions necessary to daisy chain a
maximum of four units at the user's option.
The last drive on the daisy chain terminates
the interface. The terminations are accom-
plished by a resistor array plugged into a DIP
socket.
The TM848-1E and TM 8 48-2E drives ar e
rotating disk memories designed for random
access data entry, storage, and retrieval
applications. Typical ap plications include
1-1
INTERNAL TRIM ERASE
accuracy.
COMPACT SIZE
ACTIVITY INDICATOR
DIRECT DRIVE, BRUSHLESS D. C.
MOTOR
INDUSTRY STANDARD INTERFACE
CO MPATI B ILITY
DISKETTE LEVER LOCK SOLENOID
The reduced size of the drive occupies only
one-half the mounting space required for a
conventional drive.
The spindle motor i s a cry stal controlled,
direct drive, brushless D. C. motor for
improved motor start time, and speed
The drive provides the control signals neces-
sary for proper trim erasure of data.
The drive is compatible with controllers that
use an industry standard interface.
An activity indicator, located on the front
panel, is automatically illuminated when the
drive is selected. This front panel L.E.D. is
also used as an indicator in the diagnostic
mode.
normal operation. Each drive consists of a
direct drive, spindle system, a head positioning
system, and a read/write system.
The TM848-1E is a single-sided drive. The
TM848-2E is a double-sided drive. The only
difference between the tw o drives is the
number of heads. The circuit board is identical
for both models.
When the diskette lever is opened, access is
provided for the insertion of a diskette. The
diskette's jacket is accurately positioned by
plastic guide rails. Its location is ensured by
the back stop and disk ejector.
Closing th e di s kette lever activates t h e
cone/clamp system, r esulting in accurate
centering and clamping of the diskette to the
drive hub. The drive hub is driven at a con-
stant speed o f 360 RPM by a cry st a l-
controlled, direct drive, brushless D. C. motor.
The head is l oaded into contact with the
recording medium wh enever t he di s kette
lever is latched.
The heads are positioned over the desired
track by means of a stepper motor/band
assembly and its associated electronics. This
positioner uses a 3.6 degree rotation to cause a
one track linear movement.
When a write-protected diskette is inserted
into the drive, the Write Protect sensor dis-
ables the write electronics of the drive, and a
Write Protect status output signal is available
to the interface. When performing a w r ite
operation, a 0.013-inch wide, nominal, data
track is recorded. Then, this track is tunnel
erased to 0.012-inch, nominal.
Data recovery electronics include a low-level
read ampli fier, fi l t er, differentiator, zero
crossover detector, and digitizing circuits. No
data-clock separation is provided.
In addition, the drive is supplied with the fol-
lowing sensor systems:
The diskette lever lock solenoid is controlled
by the host system.
1.4 FUNCTIONAL DESCRIPTION
1. A Track 0 s ensor detects when th e
Head/Carriage Assembly is positioned
over Track 0.
2. The TM848-2E has two index sensors,
each consisting of an infr ared L.E.D.
The drives are fully self-contained, and
require n o oper ator int ervention d uring
1-2
light source and a phototransistor, posi-
tioned to generate a signal when an
index hole on the diskette is detected.
The drive can determine if a single-
sided or dou ble-sided d i s kett e i s
installed. This output signal is present
at the interface.
Opening and closing the diskette lever i s
required to repeat a test that has failed. The
diskette lever must be left open to complete
an error cycle.
1.5 PHYSICAL DESCRIPTION
3. A Wr ite Protect sensor disables the
write electronics when a write-enable
tab is removed from the diskette.
POWER ON SELF- TESTS
A representative drive is shown in Figure 1-1.
The drive can be mounted in a vertical or hori-
zontal plane. However, the logic circuit board
must be on the uppermost side when the drive
is mounted horizontally.
The drive conducts a power on self-test as part
of the normal power on sequence. Two of the
tests do not require a diskette to be inserted.
These tests are: the head carriage stepping in,
away from, Track 0, and the head carriage
stepping out toward Track 0. Failure of either
of these tests is indicated on the front panel
L.E.D. by the following flashing sequence:
3 flashes, then 2: Fails to s t ep in fr o m
Track 0 or Tr a c k 0
sensor is always equal
to zero.
The spindle is rotated by a direct drive, brush-
less D. C. motor with an integral tachometer.
The crystal-controlled serv o c i r cuit and
tachometer control the speed of the spindle.
Operator access for diskette loading is pro-
vided via a horizontal slot located at the front
of the drive.
3 flashes, then 3: Fails to st e p out t o
Track 0 or Tr ack 0
sensor is always equal
to one.
The read/write double-head assembly is posi-
tioned by a split band positioner mounted to a
microprocessor-controlled stepper motor. The
read/write heads are glass-bonded, ferrite/
ceramic structures with a lif e expectancy of
15,000 operating hours.
A third test monitors the index sensors when-
ever the diskette lever is closed, and must
have a diskette inserted into the drive. If the
diskette lever is closed without a diskette in
place, or the spindle motor fails to operate, an
error message flashes on the front panel
L.E.D. in the following sequence:
3 flashes, then 4: No index pu l se wit h
The control electronics of the driv e ar e
mounted on a printed circuit board located
above the chassis. Power and interface signals
are routed t hr ough co nn ectors pl ugging
directly into the logic circuit board. A second
circuit board, mounted under the drive, oper-
ates the brushless D. C. spindle motor.lever closed.
1-3
~>GURp y.y
OISK Qp]yp
SECTION 2
PRODUCT SPECIFICATIONS
INTRODUCTION
This section contains the mechanical, electrical, reliability, and environmental specifications for the
TM848-1E and TM848-2E drives.
2.1 MECHANICAL SPECIFICATIONS
Figure 2-1 contains the physical dimensions of the drive.
2.2 ELECTRICAL AND OPERATIONAL SPECIFICATIONS
The electrical and operational specifications are located in Table 2-1.
2.3 RELIABILITY SPECIFICATIONS
The reliability specifications are located in Table 2-2.
2.4 ENVIRONMENTAL SPECIFICATIONS
The environmental specifications are located in Table 2-3.
1 7 9049-001
REY. A
CRVI C I E3 f l COR ORA ON,CH TSWORTII,CAL O • IA 9 1
2-1
6-32 THD
THRU 4 PLCS
(2 EACH SIDE)
Q5)
Go
O0
1 2.00
' (304.8 MM)
/ 0.149 DIA TOP X
0.156 DIA BOTTOM
X 0.430 DEEP
4 PLCS
8.00
(203.2 MM)
o o
o o
o)
• Oo
3.50
(88.9 MM)
0 o
p
L~o
/
1.20
(30.5 MM)
0.75~ '
(19.0 MM)
1.60
(40.6 MM)
(25.4 MM)
7. 50
(190.5 MM)
1.650
(41.5 MM)
0.52
(13.2 MM)
8.550
(217.2 MM)
2.025
(51.4 MM)
2.300
(58.4 MM)
NOTES: 1. DIMENSIONS ARE GIVEN IN INCHES. METRIC EQUIVALENTS ARE IN PARENTHESES.
2. TOLERANCE ON ALL DIMENSIONS IS
H-.020 INCH.
3. WEIGHT IS APPROXIMATELY 5.7 POUNDS.
FIGURE 2-1
DISK DRIVE OUTLINE DRAWING
1 79049-001
REV. A
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2-2
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